127
127 is a prime, odd, a calendar year.
127 (one hundred twenty-seven) is an odd 3-digit number. It is a prime number — divisible only by 1 and itself. It is a Mersenne prime. Written other ways, in Roman numerals it is CXXVII and in binary, 1111111.
Interestingness
Historical context — 127 AD
Calendar year
Year 127 (CXXVII) was a common year starting on Tuesday of the Julian calendar.
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Historical context — 127 BC
Calendar year
Year 127 BC was a year of the pre-Julian Roman calendar.
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Year facts
- Year type
-
Common year
Standard 365-day year; not divisible by 4 (or divisible by 100 but not 400).
- Days in year
- 365
- ISO weeks
- 52
- Started on
-
Wednesday
January 1, 127
- Ended on
-
Wednesday
December 31, 127
- Friday the 13ths
-
1
One Friday the 13th this year.
- Decade
-
120s
120–129
- Century
-
2nd century
101–200
- Millennium
-
1st millennium
1–1000
- Years ago
-
1,899
1899 years before 2026.
In other calendars
- Hebrew
-
3887 / 3888 AM
Rosh Hashanah falls in September/October.
- Chinese
-
Year of the zodiac:Fire zodiac:Rabbit
Sexagenary cycle position 4 of 60. Lunar new year falls in late January / mid-February.
- Buddhist Era
-
670 BE
Counted from the parinirvana of the Buddha (Theravada / Thai / Sri Lankan convention).
- Ethiopian
-
119 / 120 ET
Year boundary at Enkutatash (September 11/12).
- Indian National (Saka)
-
49 / 48 Saka
Indian national calendar; year starts in March.
Properties
Primality
127 is prime. It has exactly two divisors: 1 and itself.
Divisors & multiples
Sums & aliquot sequence
Continued fraction of √n
√127 = [11; (3, 1, 2, 2, 7, 11, 7, 2, 2, 1, 3, 22)]
Period length 12 — the block in parentheses repeats forever.
Representations
- In words
- one hundred twenty-seven
- Ordinal
- 127th
- Roman numeral
- CXXVII
- Binary
- 1111111
- Octal
- 177
- Hexadecimal
- 0x7F
- Base64
- fw==
- One's complement
- 128 (8-bit)
- Scientific notation
- 1.27 × 10²
- As a duration
- 127 s = 2 minutes, 7 seconds
As an angle
Historical numeral systems
- Babylonian (base 60)
- 𒁹𒁹 𒁹𒁹𒁹𒁹𒁹𒁹𒁹
- Egyptian hieroglyphic
- 𓍢𓎆𓎆𓏺𓏺𓏺𓏺𓏺𓏺𓏺
- Greek (Milesian)
- ρκζʹ
- Mayan (base 20)
- 𝋦·𝋧
- Chinese
- 一百二十七
- Chinese (financial)
- 壹佰貳拾柒
Digit at this position in famous constants
- π — Pi (π)
- Digit 127 = 4
- e — Euler's number (e)
- Digit 127 = 3
- φ — Golden ratio (φ)
- Digit 127 = 3
- √2 — Pythagoras's (√2)
- Digit 127 = 6
- ln 2 — Natural log of 2
- Digit 127 = 0
- γ — Euler-Mascheroni (γ)
- Digit 127 = 4
Also seen as
As an ASCII codepoint, 127 is DEL (delete). ASCII control character.
As an unsigned 32-bit integer, this is the IPv4 address 0.0.0.127.
- Address
- 0.0.0.127
- Class
- reserved
- IPv4-mapped IPv6
- ::ffff:0.0.0.127
Unspecified address (0.0.0.0/8) — "this network" placeholder.
Heard as a frequency, 127 Hz is closest to:
- Concert pitch (A4 = 440 Hz): B2 (123.5 Hz, +49¢ — about midway to C3)
- Scientific pitch (C4 = 256 Hz): C3 (128 Hz, -14¢)
- Baroque pitch (A4 = 415 Hz): C♯3 (130.7 Hz, -50¢ — about midway to C3)
As a MIDI note number, 127 is G9 (12543.9 Hz at concert pitch) — the highest MIDI note.
On an ingredients label, E127 is Erythrosine, a food colour.
Related reading
- Mersenne primes — Primes one less than a power of two — the record-holders for the largest known primes for over a century.
- Egyptian hieroglyphic numerals — Seven hieroglyphs for every power of ten, from a single stroke to a million.